A pressure-sensitive adhesive may be used for various uses. For example, the pressure-sensitive adhesive may be used for the purpose of adhering an optical film, such as a polarizing plate or a retardation film on a display device, such as a liquid crystal display device (hereinafter referred to as an “LCD device”) or for the purpose of mutually laminating the optical films, such as the polarizing plate or the retardation film. In some cases, the pressure-sensitive adhesive that is used for the optical film or the like requires cohesive strength, adhesiveness, re-workability, or low light leakage characteristic together with excellent transparency. For example, Patent Documents 1 to 3 propose an optical adhesive composition so as to achieve the physical properties as described above.
In addition, a pressure-sensitive adhesive may require an antistatic property if necessary, and for example, Patent Documents 4 and 5 disclose the pressure-sensitive adhesive capable of securing the antistatic property.